ryan60isu

I have a 2007 550i with 72k and a strange noise in the engine bay.

Any idea what this might be? I'm going to take it to the dealer in the next day or two, but want to prepare for the bill.

Here is a short video of the noise:

Thanks!

pcy

Sounds like some pulley is wobbling really bad. Take a flash light and look at all the pullies on the drive belt and see if any of the pullies are wobbling.

If it was me, I would've dropped the drive belt and run the engine for few seconds to see if the noise is internal to the engine or external (one of the accessories on the belt).

ryan60isu

Thanks for the reply. I've been scouring the forum and youtube and found this video and think it might be similar.

I'm going to take your advice and look with a flashlight and see if it looks anything like the video posted. I'm not much of a gear head, is there anything I should be cognizant of?

545iMike

Probably water pump.

dingolfing

Yep, most likely water pump. Mine sounds very similar and I dropped the belt and tugged at the pulley. The bearings are going bad and it even makes noise if I spin it with my hand. Time to find a spare weekend to fix now...

EddieboyS

Agree, I would have the water pump checked first.

dinan550

Sounds like the water pump going bad. Mine made a similar knocking/rattling noise around 64k miles. The mechanic popped the hood and immediately diagnosed a faulty water pump. Paid about $900 for them to replace the pump, thermostat, and some other related parts.